U.S. patent number 4,708,363 [Application Number 06/888,734] was granted by the patent office on 1987-11-24 for mechanism for limiting angular movement in steering systems for motor vehicles.
This patent grant is currently assigned to Honda Giken Kogyo Kabushiki Kaisha. Invention is credited to Koichi Hata.
United States Patent |
4,708,363 |
Hata |
November 24, 1987 |
Mechanism for limiting angular movement in steering systems for
motor vehicles
Abstract
An angular movement limiting mechanism is incorporated in a
steering system for a motor vehicle includes a steering handle, a
pair of steerable wheels, a pair of knuckles on which the steerable
wheels are rotatably supported, a pair of knuckle supporting
members on which the knuckles are angularly movably supported, and
a pair of tie rods operatively coupled between the steering handle
and the knuckles for transmitting angular movement of the steering
handle to the knuckles. The angular movement limiting mechanism
comprises a pair of stoppers mounted on the knuckle supporting
members, respectively, and engageable with the knuckles,
respectively, for limiting angular movement of the knuckles. The
stoppers and the knuckles are relatively positioned such that when
the steering handle is turned through a maximum angle, there is a
clearance kept between the knuckle coupled to the tie rod being
pushed and the stopper associated therewith.
Inventors: |
Hata; Koichi (Tokyo,
JP) |
Assignee: |
Honda Giken Kogyo Kabushiki
Kaisha (Tokyo, JP)
|
Family
ID: |
15700059 |
Appl.
No.: |
06/888,734 |
Filed: |
July 21, 1986 |
Foreign Application Priority Data
|
|
|
|
|
Jul 19, 1985 [JP] |
|
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60-159732 |
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Current U.S.
Class: |
280/771;
280/93.502 |
Current CPC
Class: |
B60B
27/0005 (20130101); B62D 7/16 (20130101); B62D
7/00 (20130101); B60K 17/16 (20130101) |
Current International
Class: |
B60B
27/00 (20060101); B60K 17/16 (20060101); B62D
7/16 (20060101); B62D 7/00 (20060101); B60G
001/00 () |
Field of
Search: |
;280/771,95R,96.1,94,774,675 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Bertsch; Richard A.
Attorney, Agent or Firm: Weiner; Irving M. Carrier; Joseph
P. Burt; Pamela S.
Claims
I claim:
1. A steering system for a motor vehicle, comprising:
a steering handle;
a pair of steerable wheels;
a pair of knuckles on which said steerable wheels are rotatably
supported, each said knuckle having a pair of front and rear
stopper portions;
a pair of knuckle supporting members on which said knuckles are
angularly movably supported;
a pair of tie rods operatively coupled between said steering handle
and said knuckles for transmitting angular movement of said
steering handle to said knuckles;
a pair of stoppers mounted on said knuckle supporting members,
respectively, and engageable with said stopper portions of said
knuckles, respectively, for limiting angular movement of said
knuckles; and
said stopper and said knuckles being relatively positioned such
that when said steering handle is turned through a maximum angle,
there is a clearance kept between the knuckle coupled to the tie
rod being pushed and the stopper associated therewith.
2. A steering system for a motor vehicle, comprising:
a steering handle;
a pair of steerable wheels;
a pair of knuckles on which said steerable wheels are rotatably
supported, each said knuckle having a pair of front and rear
stopper portions;
a pair of members with respect to which said knuckles are angularly
movable;
a pair of tie rods operatively coupled between said steering handle
and said knuckles for transmitting angular movement of said
steering handle to said knuckles;
a pair of stoppers mounted on said members, respectively, and
engageable with said stopper portions of said knuckles,
respectively, for limiting angular movement of said knuckles;
and
said stoppers and said knuckles being relatively positioned such
that when said steering handle is turned through a maximum angle,
one of said knuckles which is coupled to the tie rod that is pulled
is brought into abutment against the stopper associated therewith
earlier than the other knuckle abuts against the stopper associated
therewith.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a mechanism for limiting angular
movement in a steering system for a motor vehicle of the type in
which a steering handlebar and the knuckles of steerable wheels are
operatively coupled by a connecting mechanism including rods.
2. Description of the Relevant Art
Steering systems for motor vehicles are generally constructed such
that the angular movement of a steering handlebar is transmitted to
a steering shaft to enable a link mechanism including tie rods to
turn knuckles for thereby steering steerable wheels connected to
the knuckles. To prevent the steerable wheels from being turned
beyond a certain angular range, into physical interference with
other elements, a stopper mechanism is disposed for limiting the
angular movement of the steering handlebar and the knuckles to a
desired angular range. The stopper mechanism has two stoppers for
engagement with the knuckles, respectively.
Due to manufacturing errors and other factors, however, it is
impossible for the knuckles of the steerable wheels to be brought
into simultaneous abutment against the respective stoppers. With
such an arrangement, when the knuckle coupled to the tie rod which
is being subjected to a push engages its stopper earlier than the
knuckle coupled to the tie rod which is being subjected to a pull,
the steering handlebar can further be turned to a certain extent
while forcibly flexing the tie rod being pushed with its knuckle in
engagement with the stopper. This action undesirably prevents the
driver from feeling a sufficient degree of firmness on the steering
handlebar when it is turned to the limits of its steering
range.
SUMMARY OF THE INVENTION
According to the present invention, there is provided a steering
system for a motor vehicle, comprising a steering handle, a pair of
steerable wheels, a pair of knuckles on which the steerable wheels
are rotatably supported, a pair of knuckle supporting members on
which the knuckles are angularly movably supported, a pair of tie
rods operatively coupled between the steering handle and the
knuckles for transmitting angular movement of the steering handle
to the knuckles, and a pair of stoppers mounted on the knuckle
supporting members, respectively, and engageable with the knuckles,
respectively, for limiting angular movement of the knuckles. The
stoppers and the knuckles are relatively positioned such that when
the steering handle is turned through a maximum angle, there is a
clearance kept between the other knuckle coupled to the tie rod
being pushed and the stopper associated therewith.
Therefore, it is an object of the present invention to provide a
mechanism for limiting angular movement in a steering system for a
motor vehicle, which mechanism is constructed to prevent a tie rod
which is being pushed from being flexed when a steering handlebar
is turned through a maximum angle.
Another object of the present invention is to provide such a
limiting mechanism which is capable of absorbing, to a certain
extent, external forces which are applied to a wheel supported on a
knuckle coupled to a tie rod being pushed by the steering system.
Such external forces otherwise tend to undesirably pull the tie rod
when a steering handlebar is turned through a maximum angle.
The above and further objects, details and advantages of the
present invention will become apparent from the following detailed
description of a preferred embodiment thereof, when read in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view, partly in cross section, of a steering
system to which an angular movement limiting mechanism according to
the present invention is applicable;
FIG. 2 is an enlarged cross-sectional view taken along line II--II
of FIG. 1;
FIG. 3 is a bottom view of a knuckle holder and a knuckle, showing
an angular movement limiting mechanism of the present invention;
and
FIG. 4 is a diagrammatic plan view of a steering system
incorporating an angular movement limiting mechanism of the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows a steering system incorporated in a four-wheel buggy
with a riding saddle. The buggy includes a vehicle frame 1 with a
swing arm 2 being vertically swingably mounted on a front end
thereof. An axle case 3 is supported on the front end of the swing
arm 2. A steering pivot arm 5 is horizontally pivotally mounted by
an upward pivot shaft 4 on the upper surface of a longitudinally
centrally portion of the axle case 3. The pivot arm 5 comprises a
lateral arm member 5a and a rear arm member 5b.
A vertically extending steering shaft 6 which is coupled to a
steering handlebar (described later on) is disposed behind the
steering pivot arm 5, and joined to an arm 7 that is angularly
movable in a horizontal plane in unison with the steering shaft 6.
The arm 7 has its distal end operatively coupled by a drag link 8
to the lateral arm member 5a of the steering pivot arm 5 so that
the arm 7 and the lateral arm member 5a will be turned in the same
direction.
As illustrated in FIG. 2, a knuckle holder 9 is fixed to each of
the opposite ends of the axle case 3 and includes upper and lower
arms 9a, 9b on which a knuckle 12 is mounted by upper and lower
kingpins 10 and bearings 11, having a substantially vertical common
axis, for substantially horizontal angular movement about the
common axis. As shown in FIG. 1, the knuckles 12 on the respective
knuckle holders 9 have rear extensions 13 with rear ends thereof
operatively coupled to the rear arm member 5b of the steering pivot
arm 5 by tie rods 14a, 14b, respectively. As shown in FIG. 2, each
of the knuckles 12 has an outwardly projecting sleeve 15 in which a
hub 18 of a steerable front wheel 17 is rotatably supported by a
bearing 16.
As shown in FIG. 1 the swing arm 2 is substantially aligned in
parallel with a drive shaft 19, which drive shaft is operatively
coupled to an axle 23, housed in the axle case 3, by a driver gear
20, a driven gear 21, and a differential gear mechanism 22. The
axle 23 has outer ends each respectively extending into a
corresponding knuckle holder 9 and coupled to a spindle 24 (FIG. 2)
through a constant-velocity joint. The spindle 24 is splined to the
inner peripheral surface of the hub 18 for driving the front wheel
17.
As illustrated in FIG. 3, a stopper 25 projects donwardly from the
lower surface of the lower arm 9b of the knuckle holder 9. The
knuckle 12 has on its lower portion a pair of front and rear
stoppers 26a, 26b positioned for engagement with the stopper 25 to
limit angular movement of the knuckle 12 to a certain angular
range.
FIG. 4 diagrammatically shows a steering system incorporating an
angular movement limiting mechanism according to the present
invention. The steering shaft 6 has an upper end secured to the
center of a handlebar 27 to which a stopper 28 is affixed. Another
stopper 29 is secured to a head pipe 30 for abutment against the
stopper 28.
The arm 7 fixed to the steering shaft 6 and the steering pivot arm
5 are operatively interconnected by the drag link 8, and the
steering pivot arm 5 and the knuckles 12 are operatively
interconnected by the tie rods 14a, 14b, respectively, as described
above. Angular movement of the steering handlebar 27 is limited by
abutting engagement between the stoppers 28, 29, whereas angular
movement of the knuckles 12 is limited by abutting engagement
between the stopper 25 and the stoppers 26a, 26b. When the knuckle
12 coupled to the tie rod 14a subjected to a pull, i.e., the
knuckle 12 of the wheel on an inner turning circle, is held in
abutment against the stopper 25, there is a small clearance
.DELTA.S kept between the knuckle 12 coupled to the tie rod 14b
subjected to a push, i.e., the knuckle 12 of the wheel on an outer
turning circle. Irrespective of whether the motor vehicle makes a
right turn or a left turn, there is a small clearance created
between the stopper 26a of the knuckle 12 on the outer wheel and
the stopper 25 of the corresponding knuckle holder 9 when the
stopper 26b of the knuckle 12 on the inner wheel and the stopper 25
of the corresponding knuckle holder 9 abut against each other.
If the steering handlebar 27 is turned counterclockwise as shown in
FIG. 4 to make a left turn, the steering shaft 6 causes the arm 7
and the drag link 8 to turn the steering pivot arm 5
counterclockwise for thereby pulling the lefthand knuckle 12
through the tie rod 14a so that the lefthand knuckle 12 is turned
counterclockwise. As the knuckles 12 are angularly moved
counterclockwise, the front wheels 17 are turned to steer the motor
vehicle to the left. Similarly, when the steering handlebar 27 is
turned clockwise, the front wheels 17 are turned to steer the motor
vehicle to the right.
When the handlebar 27 is fully turned counterclockwise under a
steering force Fs, the tie rod 14a is subjected to a pulling force
Fa and the lefthand knuckle 12 coupled to the tie rod 14a is
angularly moved through a maximum angle .theta. until the rear
stopper 26b thereof engages the rear edge of the lefthand stopper
25. Since the tie rod 14a will not be flexed even if the steering
force Fs is continuously applied to the handlebar 27, the driver
who turns the handlebar 27 feels a sufficient degree of firmness on
the handlebar 27 which is now prevented from being turned further.
At this time, the front stopper 26a of the righthand knuckle 12
coupled to the tie rod 14b subjected to a pushing force Fb is
spaced the clearance .DELTA.S from the front edge of the righthand
stopper 25. When an external force W is imposed on the wheel 17 on
the righthand knuckle 12, tending to turn the wheel 17
counterclockwise, the external force W is absorbed to a certain
extent by the clearance .DELTA.S, after which the front stopper 26a
of the righthand knuckle 12 is brought into abutting engagement
with the righthand stopper 25. Therefore, any adverse effects which
the application of such an external force W has on the steering
system can be held to a minimum.
Although there has been described what is at present considered to
be the preferred embodiment of the present invention, it will be
understood that the invention may be embodied in other specific
forms without departing from the spirit or essential
characteristics thereof. The present embodiment is therefore to be
considered in all aspects as illustrative, and not restrictive. The
scope of the invention is indicated by the appended claims rather
than by the foregoing description.
* * * * *